This question is a bit vague. But it seems like you need to explore why the pen may be a mightier weapon than the more likely sword. Yes, swords and more typical weapons are quite mighty. But their impact may be argued to be fleeting. When one uses the pen to record one's attacks (be they on society, politics, etc.) these attacks gain a permanency. They may reach a more vast audience. When one records one's thoughts, one has the time to think and contemplate exactly how to phrase one's arguments instead of an instantaneous statement.

It would probably benefit you to research some famous speeches or essays written as protest and exmaine their lasting impact on the world.